Safety and Immunogenicity of Inactivated Whole Virion COVID-19 Vaccine CoviVac in Clinical Trials in 18-60 and 60+ Age Cohorts.

We present the results of a randomized, double-blind, placebo-controlled, multi-center clinical trial phase I/II of the tolerability, safety, and immunogenicity of the inactivated whole virion concentrated purified coronavirus vaccine CoviVac in volunteers aged 18-60 and open multi-center comparative phase IIb clinical trial in volunteers aged 60 years and older. The safety of the vaccine was assessed in 400 volunteers in the 18-60 age cohort who received two doses of the vaccine (n = 300) or placebo (n = 100) and in 200 volunteers in 60+ age cohort all of whom received three doses of the vaccine. The studied vaccine has shown good tolerability and safety. No deaths, serious adverse events (AEs), or other significant AEs related to vaccination have been detected. The most common AE in vaccinated participants was pain at the injection site (p < 0.05). Immunogenicity assessment in stage 3 of Phase II was performed on 167 volunteers (122 vaccinated and 45 in Placebo Group) separately for the participants who were anti-SARS-CoV-2 nAB negative (69/122 in Vaccine Group and 28/45 in Placebo Group) or positive (53/122 in Vaccine Group and 17/45 in Placebo Group) at screening. On Day 42 after the 1st vaccination, the seroconversion rate in participants who were seronegative at screening was 86.9%, with the average geometric mean neutralizing antibody (nAB) titer of 1:20. A statistically significant (p < 0.05) increase in IFN-γ production by peptide-stimulated T-cells was observed at Days 14 and 21 after the 1st vaccination. In participants who were seropositive at screening but had nAB titers below 1:256, the rate of fourfold increase in nAB levels was 85.2%, while in the participants with nAB titers > 1:256, the rate of fourfold increase in nAB levels was below 45%; the participants who were seropositive at screening of the 2nd vaccination did not lead to a significant increase in nAB titers. In conclusion, inactivated vaccine CoviVac has shown good tolerability and safety, with over 85% NT seroconversion rates after complete vaccination course in participants who were seronegative at screening in both age groups: 18-60 and 60+. In participants who were seropositive at screening and had nAB titers below 1:256, a single vaccination led to a fourfold increase in nAB levels in 85.2% of cases. These findings indicate that CoviVac can be successfully used both for primary vaccination in a two-dose regimen and for booster vaccination as a single dose in individuals with reduced neutralizing antibody levels.

Hydrophobic Rose Bengal Derivatives Exhibit Submicromolar-to-Subnanomolar Activity against Enveloped Viruses.

Rose Bengal (RB) is an anionic xanthene dye with multiple useful biological features, including photosensitization properties. RB was studied extensively as a photosensitizer, mostly for antibacterial and antitumor photodynamic therapy (PDT). The application of RB to virus inactivation is rather understudied, and no RB derivatives have been developed as antivirals. In this work, we used a synthetic approach based on a successful design of photosensitizing antivirals to produce RB derivatives for virus photoinactivation. A series of n-alkyl-substituted RB derivatives was synthesized and evaluated as antiviral photosensitizers. The compounds exhibited similar 1O2 generation rate and efficiency, but drastically different activities against SARS-CoV-2, CHIKV, and HIV; with comparable cytotoxicity for different cell lines. Submicromolar-to-subnanomolar activities and high selectivity indices were detected for compounds with C4-6 alkyl (SARS-CoV-2) and C6-8 alkyl (CHIKV) chains. Spectrophotometric assessment demonstrates low aqueous solubility for C8-10 congeners and a significant aggregation tendency for the C12 derivative, possibly influencing its antiviral efficacy. Initial evaluation of the synthesized compounds makes them promising for further study as viral inactivators for vaccine preparations.

Safety and immunogenicity of inactivated whole virion vaccine CoviVac against COVID-19: a multicenter, randomized, double-blind, placebo-controlled phase I/II clinical trial

We present the results of a randomized, double-blind, placebo-controlled, multi-center clinical trial of the tolerability, safety, and immunogenicity of the inactivated whole virion concentrated purified coronavirus vaccine CoviVac in adult volunteers aged 18-60. Safety of the vaccine was assessed in 398 volunteers who received two doses of the vaccine (n=298) or placebo (n=100). The studied vaccine has shown good tolerability and safety. No deaths, serious adverse events (AE), or other significant AE related to vaccination have been detected. The most common AE in vaccinated participants was pain at the injection site (p<0.05). Immunogenicity assessment was performed in 167 volunteers (122 vaccinated and 45 in Placebo Group) separately for the participants who were anti-SARS-CoV-2 nAB negative (69/122 in Vaccine Group and 28/45 in Placebo Group) or positive (53/122 in Vaccine Group and 17/45 in Placebo Group) at screening. At Day 42 after the first immunization the seroconversion rate in participants who were seronegative at screening was 86.9% with average the geometric mean neutralizing antibody (nAB) titer of 1:20. Statistically significant (p<0.05) increase of IFN-{gamma} production by peptide-stimulated T-cells was observed at Days 14 and 21 after the first immunization. In participants who were seropositive at screening but had nAB titers below 1:256 the rate of 4-fold increase in nAB levels was 85.2%, while in the participants with nAB titers >1:256 the rate of 4-fold increase in nAB levels was below 45%. For the participants who were seropositive at screening the second immunization did not lead to a significant increase in nAB titers. In conclusion, inactivated vaccine CoviVac has shown good tolerability and safety, with 86.9% seroconversion rates in participants, who were seronegative at screening. In participants who were seropositive at screening and had nAB titers below 1:256, a single immunization lead to a 4-fold increase in nAB levels in 85.2% cases.

Probing GFP Chromophore Analogs as Anti-HIV Agents Targeting LTR-III G-Quadruplex.

Green fluorescent protein (GFP) chromophore and its congeners draw significant attention mostly for bioimaging purposes. In this work we probed these compounds as antiviral agents. We have chosen LTR-III DNA G4, the major G-quadruplex (G4) present in the long terminal repeat (LTR) promoter region of the human immunodeficiency virus-1 (HIV-1), as the target for primary screening and designing antiviral drug candidates. The stabilization of this G4 was previously shown to suppress viral gene expression and replication. FRET-based high-throughput screening (HTS) of 449 GFP chromophore-like compounds revealed a number of hits, sharing some general structural features. Structure-activity relationships (SAR) for the most effective stabilizers allowed us to establish structural fragments, important for G4 binding. Synthetic compounds, developed on the basis of SAR analysis, exhibited high LTR-III G4 stabilization level. NMR spectroscopy and molecular modeling revealed the possible formation of LTR-III G4-ligand complex with one of the lead selective derivative ZS260.1 positioned within the cavity, thus supporting the LTR-III G4 attractiveness for drug targeting. Selected compounds showed moderate activity against HIV-I (EC50 1.78-7.7 µM) in vitro, but the activity was accompanied by pronounced cytotoxicity.

Activation and damage of endothelial cells upon hypoxia/reoxygenation. Effect of extracellular pH.

Disturbances of blood flow upon vascular occlusions and spasms result in hypoxia and acidosis, while its subsequent restoration leads to reoxygenation and pH normalization (re-alkalization) in ischemic sites of the vascular bed. The effect of hypoxia/reoxygenation on activation and stimulation of apoptosis in cultured human endothelial cells was studied. The cells were subjected to hypoxia (2% O2, 5% CO2, 93% N(2)) for 24 h followed by reoxygenation (21% O2, 5% CO2, 74% N(2)) for 5 h. Reoxygenation was carried out at different pH-6.4 (preservation of acidosis after hypoxia), 7.0, and 7.4 (partial and complete re-alkalization, respectively). Hypoxia only slightly (by approximately 30%) increased the cell adhesion molecule ICAM-1 content on the cell surface, whereas reoxygenation more than doubled its expression. The reoxygenation effect depended on the medium acidity, and ICAM-1 increase was more pronounced at pH 7.0 compared to that at pH 6.4 and 7.4. Neither hypoxia nor reoxygenation induced expression of two other cell adhesion molecules, VCAM and E-selectin. Incubation of cells under hypoxic conditions but not reoxygenation stimulated secretion of von Willebrand factor and increased its concentration in the culture medium by more than 4 times. The percentage of cells containing apoptosis marker, activated caspase-3, was increased by approximately 1.5 times upon hypoxia as well as hypoxia/reoxygenation. Maximal values were achieved when reoxygenation was performed at pH 7.0. These data show that hypoxia/reoxygenation stimulate pro-inflammatory activation (ICAM-1 expression) and apoptosis (caspase-3 activation) of endothelial cells, and the extracellular pH influences both processes.

[The structural component of the vascular adrenoreactivity of the skeletal muscles in normo- and hypertensive rats]. / Strukturnyi komponent adrenoreaktivnosti sosudov skeletnykh myshts normo- i gipertenzivnykh krys.

In anesthetized normotensive (WKY) and spontaneously hypertensive (SHR) rats the adrenoreactivity in the maximum dilated vessels of hind leg skeletal muscles was compared. Adrenoreactivity mentioned above has been registered as an amplitude of changes of hydraulic resistance (R), hydrostatic capillary pressure (Pc) and capillary filtration coefficient (CFC) to noradrenaline infusion in the vascular bed of perfused skeletal muscles. Resistance changes were more considerable in experiments on the SHR comparatively to those in the WKY. Changes of CFC as well as Pc in both strains were not statistically differed. The data obtained confirm Folkow's hypothesis about increased adrenoreactivity of the resistance vessels in hypertensive mammals due to structural changes of the vascular bed.

[The effect of high-molecular compounds on the rheological properties of the blood and on the reactivity of the skeletal muscle vessels]. / Vliianie vysokomolekuliarnykh soedinenii na reologicheskie svoistva krovi i reaktivnost' sosudov skeletnoi myshtsy.

The administration of polymers into the vascular bed of the m. gastrocnemius and in vitro did not affect the postocclusion hyperemia but in changed the venous outflow from the muscle, the change having a phasic character. The effects of concentrations and molecular mass of the polymers on the blood rheological properties were more obvious in vitro. Dextran-20 thousand most favourably affects the blood viscosity whereas the least favourable one belongs to polyoxyethylene-20 thousand. The polymers with molecular mass about 500 thousand in small concentrations reduce the viscosity of the blood, in larger concentrations they enhance it increasing the erythrocytes aggregation.